SAP-C02 Design for New Solutions Practice Question
A company is designing a serverless application using AWS Lambda, Amazon API Gateway, and Amazon DynamoDB. The application experiences sudden spikes in traffic. Which AWS service should be used to handle the traffic spikes without losing any requests?
⚠ Common exam trap
SAP-C02 often tests the confusion between SNS (push, no buffering) and SQS (pull, buffering), causing candidates to pick SNS when the requirement is to avoid losing requests during spikes.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Amazon SQS
Amazon SQS is a fully managed message queuing service that decouples application components and buffers requests during traffic spikes. By placing an SQS queue between API Gateway and Lambda (or between Lambda and DynamoDB), the system can absorb sudden bursts of traffic without losing requests, as messages are durably stored until processed. This is the standard pattern for handling spiky serverless workloads.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon SNS
Why it's wrong here
Amazon SNS is a pub/sub messaging service that fans messages out to subscribers; it does not buffer API Gateway requests or absorb Lambda concurrency spikes, so requests still fail. It tempts because SNS decouples components and can trigger Lambda, but the requirement is queue-based buffering, which Amazon SQS provides.
- ✗
AWS Step Functions
Why it's wrong here
Step Functions orchestrates multi-step workflows with retries and state tracking, not request buffering. It cannot absorb traffic spikes, so requests arriving beyond Lambda's concurrency limit are throttled and lost. It would be correct for coordinating long-running, multi-service business processes rather than smoothing sudden load.
- ✓
Amazon SQS
Why this is correct
Amazon SQS decouples API Gateway from Lambda, buffering burst traffic in a durable queue so no requests are lost during spikes. Lambda's concurrency limits would otherwise throttle or drop invocations; SQS absorbs the surge and enables downstream retry processing.
- ✗
Amazon Kinesis Data Streams
Why it's wrong here
Kinesis Data Streams buffers records for consumers to poll, but API Gateway cannot write incoming requests into it directly, so spikes are not absorbed at the request tier. It is tempting because Kinesis is correct for ingesting high-volume streaming data for downstream analytics or Lambda consumers.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This SAP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SAP-C02 exam.